Degeneration of the intervertebral disc is normally associated with the aging process. In some individuals disc degeneration can be precipitated by recognized disc trauma (e.g. repetitive heavy loading of the disc or an isolated disc injury) or may be a consequence of an apparently heritable condition (i.e. “juvenile disc degeneration”). Disc degeneration can involve anatomical (micro and macro anatomic) as well as biochemical alterations of the disc and tissues adjacent the disc such as the annulus and vertebral endplate. For example, disc desiccation and vertebral endplate sclerosis are intervertebral changes that can occur. Excessive loading (either singly or repetitive) can result in increased vertebral endplate ossification (i.e. increased bone formation) of the normally porous, but condensed cancellous bone. This ossification is theorized to reduce the normal diffusion of metabolites and catabolites to and from the highly vascularized vertebral body to and from the fibrocartilaginous disc space.
Degeneration can occur in a relatively asymptomatic manner or non-debilitating manner. In others, the process of disc degeneration can produce varying degrees of discomfort and disability. In the more debilitating forms of the disc degeneration, patients often seek interventions that can range from activity restrictions, NSAID treatment, and exercise therapy, to surgical management such as partial disc excision, disc resection and interbody arthrodesis (intervertebral fusion), or prosthetic disc replacement (arthroplasty).
Very few medical interventions are effective in fundamentally altering the underlying anatomic, pathophysiologic and/or biochemical changes that accompany intervertebral disc degeneration.